Screening for eye diseases has become increasingly important as the population ages in the United States and around the world. Major causes of irreversible blindness include diabetic retinopathy, macular degeneration, and glaucoma. Standard screening measures such as visual acuity testing or intraocular pressure measurement are inadequate, since these tests only identify patients late in the disease process.
Despite such limitations, there is increasing pressure to screen patients for early indicators of eye disease. For example, health maintenance organizations and governments encourage annual screening of diabetics for retinopathy. As macular degeneration can be effectively prevented or slowed by treatment with multivitamins, early detection is advantageous. It is also well-established that cupping of the optic disc is the prelude to devastating visual loss in glaucoma.
Traditionally, eye examinations have been performed using an ophthalmoscope. More recently, camera systems have been developed to image the interior of the eye. In a traditional fundus camera, the ocular fundus is illuminated by a beam of light that is projected through the pupil and onto the retina. Light reflected back from the retina is directed to an observation microscope and/or camera for observation or recording. An eye care professional is then able to review the recorded images for signs of eye disease.